JavaScript生成图形验证码

getGVerify:function (id)  {     function GVerify(options) { //创建一个图形验证码对象，接收options对象为参数      this.options = { //默认options参数值        id: "", //容器Id        canvasId: "verifyCanvas", //canvas的ID        width: "100", //默认canvas宽度        height: "30", //默认canvas高度        type: "blend", //图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母        code: ""      }       if(Object.prototype.toString.call(options) == "[object Object]"){//判断传入参数类型        for(var i in options) { //根据传入的参数，修改默认参数值          this.options[i] = options[i];        }      }else{        this.options.id = options;      }       this.options.numArr = "0,1,2,3,4,5,6,7,8,9".split(",");      this.options.letterArr = getAllLetter();       this._init();      this.refresh();    }     GVerify.prototype = {      /**版本号**/      version: '1.0.0',       /**初始化方法**/      _init: function() {        var con = document.getElementById(this.options.id);        var canvas = document.createElement("canvas");        /*this.options.width = con.offsetWidth > 0 ? con.offsetWidth : "100";        this.options.height = con.offsetHeight > 0 ? con.offsetHeight : "30";*/        canvas.id = this.options.canvasId;        canvas.width = this.options.width;        canvas.height = this.options.height;        canvas.style.cursor = "pointer";        canvas.innerHTML = "您的浏览器版本不支持canvas";        con.appendChild(canvas);        var parent = this;        canvas.onclick = function(){          parent.refresh();        }      },       /**生成验证码**/      refresh: function() {        this.options.code = '';        var canvas = document.getElementById(this.options.canvasId);        if(canvas.getContext) {          var ctx = canvas.getContext('2d');        }        ctx.textBaseline = "middle";         ctx.fillStyle = randomColor(180, 240);        ctx.fillRect(0, 0, this.options.width, this.options.height);         if(this.options.type == "blend") { //判断验证码类型          var txtArr = this.options.numArr.concat(this.options.letterArr);        } else if(this.options.type == "number") {          var txtArr = this.options.numArr;        } else {          var txtArr = this.options.letterArr;        }         for(var i = 1; i <= 4; i++) {          var txt = txtArr[randomNum(0, txtArr.length)];          this.options.code += txt;          ctx.font = '20px SimHei';          //ctx.font = randomNum(this.options.height/2, this.options.height) + 'px SimHei'; //随机生成字体大小          ctx.fillStyle = randomColor(50, 160); //随机生成字体颜色          /* ctx.shadowOffsetX = randomNum(-3, 3);          ctx.shadowOffsetY = randomNum(-3, 3);*/          ctx.shadowBlur = randomNum(-3, 3);          ctx.shadowColor = "rgba(0, 0, 0, 0.3)";          var x = this.options.width / 5 * i;          var y = this.options.height / 2;          var deg = randomNum(-30, 30);          /**设置旋转角度和坐标原点**/          ctx.translate(x, y);          ctx.rotate(deg * Math.PI / 180);          ctx.fillText(txt, 0, 0);          /**恢复旋转角度和坐标原点**/          ctx.rotate(-deg * Math.PI / 180);          ctx.translate(-x, -y);        }        /**绘制干扰线**/        for(var i = 0; i < 4; i++) {          ctx.strokeStyle = randomColor(40, 180);          ctx.beginPath();          ctx.moveTo(randomNum(0, this.options.width/2), randomNum(0, this.options.height/2));          ctx.lineTo(randomNum(0, this.options.width/2), randomNum(0, this.options.height));          ctx.stroke();        }        /**绘制干扰点**/        for(var i = 0; i < this.options.width/4; i++) {          ctx.fillStyle = randomColor(0, 255);          ctx.beginPath();          ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 2 * Math.PI);          ctx.fill();        }      },       /**验证验证码**/      validate: function(code){        var verifyCode = code.toLowerCase();        var v_code = this.options.code.toLowerCase();        if(verifyCode == v_code){          return true;        }else{          return false;        }      }    }     /**生成字母数组**/    function getAllLetter() {      var letterStr = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";      return letterStr.split(",");    }    /**生成一个随机数**/    function randomNum(min, max) {      return Math.floor(Math.random() * (max - min) + min);    }    /**生成一个随机色**/    function randomColor(min, max) {      var r = randomNum(min, max);      var g = randomNum(min, max);      var b = randomNum(min, max);      return "rgb(" + r + "," + g + "," + b + ")";    }     return new GVerify(id);  }

var verifyCode = new GVerify(id);

if(verifyCode.validate(inputCode)){   return true;}esle{   return false;}